The conventional view is that hunter-gatherers from a wide region built Göbekli Tepe when they converged there for seasonal rituals, but some people claim that they would not have had the technology or know-how to accomplish that. This has led to fanciful claims that Göbekli Tepe's builders were disciples of some lost Pleistocene civilization, or even extraterrestrials. However, the most plausible scenario is that Göbekli Tepe's builders were Neolithic villagers who resided at the site.

If you're interested in the theories that claim that Göbekli Tepe has something to do with a lost civilization, or even extraterrestrials, you might want to check out my other video that deals with this:
   • Pseudoarchaeology  

As so many of the comments here focused on the "handbags" on Pillar 43, I have since made a video on that specific topic:
   • The "Handbags" of Göbekli Tepe  

And here's the article I published on the site in 2011:
https://www.journals.uchicago.edu/doi...

And another article in which I review more recent developments about the site:
https://www.degruyter.com/document/do...

And here's an article that critiques Hancock's theory of a pre-Holocene civilization, with an emphasis on Göbekli Tepe:
https://www.skeptic.com/reading_room/...